scholarly journals A Method for Introducing Fishery Regulation Taking Advantage of Natural Fluctuation in Stock Size

1996 ◽  
Vol 62 (3) ◽  
pp. 333-339
Author(s):  
Eiji Tanaka
Author(s):  
Roli Juliet Egbe ◽  
Achoja Roland Onomu ◽  
Pius Chinwuba Ike ◽  
Isiorhovoja Rodney Akpoviri

Entrepreneurial orientation is vital to growth and development, but lacking in many small-scale enterprises. This study investigated growth and entrepreneurial orientation in the small-scale poultry subsector of Delta State, Nigeria. It also ascertained the drivers of poultry entrepreneurial orientation in the study area. A multistage sampling procedure was used to collect primary data from 180 poultry farmers, through a questionnaire. A four-point Likert scale of five items was used to measure entrepreneurial orientation from innovativeness, proactiveness, and risk-taking. The data were analyzed using descriptive and inferential statistics, including gross margins, an autoregressive lag model, and logistic regression. The majority (57.7%) of the farmers are female. The small-scale poultry entrepreneurs had an orientation that was above average. The autoregressive lag model result indicated an increase in stock size and gross margins of poultry enterprises. It was forecast that the growth trend would increase up to 2022. Furthermore, the ANOVA result was statistically significant at 0.002*** and 0.001*** for stock size and gross margins, respectively. Years of experience and training in poultry farming and noninvolvement of entrepreneurs in other occupations influence their entrepreneurial orientation. Poultriy entrepreneurs must be trained while they adopt poultry farming as their principal occupation.


2010 ◽  
Author(s):  
Bruce Allen Hearn ◽  
Byoung Youp Lee ◽  
Roger Nicholas Strange ◽  
Jenifer Piesse

1987 ◽  
Vol 44 (S2) ◽  
pp. s156-s165 ◽  
Author(s):  
Carl J. Walters

Stock assessment usually proceeds from the assumption that there are time-invariant relationships between stock size and rate processes such as recruitment, although such relationships are difficult to discern due to noise caused by factors other than stock size. There are good biological reasons not to trust this assumption in exploited populations, where persistent environmental changes and shifts in stock structure may cause various parameters to change. Graphical and statistical procedures can be used to detect this nonstationarity in historical data sets for which stock size has varied so as to repeatedly sample a range of sizes. The policy implications of nonstationarity depend on whether the changes are clearly observable as deviations from known, Song-term baseline responses. If the changes are observable, it is usually best to pretend that the current deviation will persist unless strong constraints on policy change make it necessary to plan for changes that may occur far into the future. If the changes are not observable (the usual case), then it is necessary to make a difficult policy choice between passively waiting for informative stock responses versus actively experimenting with harvest rates so as to quickly get information about responses over a range of stock sizes.


2011 ◽  
Vol 68 (7) ◽  
pp. 1488-1499 ◽  
Author(s):  
Ólafur K. Pálsson ◽  
Höskuldur Björnsson

Abstract Pálsson, Ó. K., and Björnsson, H. 2011. Long-term changes in trophic patterns of Iceland cod and linkages to main prey stock sizes. – ICES Journal of Marine Science, 68: 1488–1499. Data on the diet composition of Iceland cod (Gadus morhua) were collected in March of the years 1981–2010 and in autumn of the years 1988–2010. Capelin, northern shrimp, and euphausiids dominate the diet in all years and may be classified as the stable food of Iceland cod. Overall, total consumption by the smallest cod (20–29 cm) remained stable over the three decades, whereas that of larger fish has declined since the mid-1990s. This decline may explain the reduced growth rate of cod in recent years. Long-term, prey-specific patterns were identified in consumption, and significant trophic links were found between cod consumption and stock sizes of capelin and northern shrimp. In March, the correlation between cod consumption on capelin and capelin stock size was highly significant, a type I functional feeding response, but not significant in autumn. The correlation deteriorated in the early to mid-1990s and in the early 2000s. Increased inflow of Atlantic water into north Icelandic waters, and associated changes in capelin distribution, may have contributed to this trend. The interaction between cod consumption on northern shrimp and shrimp stock size showed a highly significant type I functional feeding response in both seasons.


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